Gallium beam lithography for superconductive structure formation
| DWPI Title: Method for forming superconductive structures of gauge e.g. pressure gauges, involves exposing region of surface with focused ion beam defining implanted region thus releasing superconductive structure held in suspension over substrate |
| Abstract: The present invention relates to the use of gallium beam lithography to form superconductive structures. Generally, the method includes exposing a surface to gallium to form an implanted region and then removing material adjacent to and/or below that implanted region. In particular embodiments, the methods herein provide microstructures and nanostructures in any useful substrate, such as those including niobium, tantalum, tungsten, or titanium. |
| Use: Method for forming superconductive structures of gauge e.g. pressure gauges such as Pirani gauges, temperature gauges, corrosion sensors for back-end-of-line (BEOL) fabrication of an IC package e.g. a hermetic IC package. |
| Advantage: The mild conditions cannot interfere with individual devices present in an integrated circuit (IC), thus allowing the methods to be employed during back-end-of-line processing when such devices are present. Hence, the gauge can be fabricated with less complexity and less expense than on-chip Pirani gauges. The parameters of the ion beam can be optimized to provide the desired implant depth, implant width, implant dose and/or beam waist. The limit on spatial selectivity is due to beam straggle, which broadens the edge of the implanted region. The parameters of the removing step can be optimized to provide the desired microstructure and/or nanostructure. |
| Novelty: The method involves exposing a region of a surface of a substrate with a focused ion beam of gallium so as to define an implanted region. The subtractive etching is a two-phase process including a first phase of anisotropic etching (152) for removing non-implanted material laterally adjacent to the implanted superconductive region to define a superconductive structure. The second phase of isotropic etching for removing non-implanted material below the implanted superconductive region, thus releasing the superconductive structure so as to be held in suspension over the substrate. |
| Filed: 6/17/2015 |
| Application Number: US14742505A |
| Tech ID: SD 13095.1 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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